Dredging apparatus



Patented Nov. 5, 1935 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to apparatus for pumping sand, gravel or othersubdivided material from, places where suflicient water is available toserve as a vehicle for the material and lend to it sufficient fluidityto enable it to respond to the pump.

In apparatus of this kind, it has long been proposed to tap into thesuction pipe, through means of elements coacting therewith after themanner of an injector, a boosting water supply furnished by anindependent pump which will largely relieve the back flow load on thematerial pump and insure an impelling force that will materiallyincrease the output of the apparatus. But in previously suggestedarrangements of this kind known to me, the boosting instrumentalitieshave been irrationally designed, with the result that the increasedcapacity bestowed has not been economically commensurate with the powerexpended for the boosting Water supply.

The object of the present invention is to provide a highly efficientconstruction of boosting instrumentality for dredging apparatus of thekind aforesaid. and the invention proceeds upon the principle of havingthe intake element of the suction pipe designed as a relatively largebarrel of substantially uniform diameter through which induced fluid(the material and its vehicular water) to the full capacity of thebarrel, will flow as a projectile free from eddy currents, serioustorsional disturbance or the like, so that when it meets the boostingwater it will be in condition to receive the latter with full andunifo-rm propelling effect throughout its circumference; also in havingthe intake end of this barrel dened by rationally narrow walls so thatmaterial may enter the barrel from points around the intake end withouthaving to travel a. substantial distance across a transverse face which,in the older arrangements, materially decreases eflciency; also inhaving the boosting or impelling column of water associated externallyand in the form of an annulus surrounding the intake barrel and inducedcolumn of fluid, as distinguished from meeting the latter in the form ofan axial jetl and with the result of causing the booster column, as itmeets the induced column within the diminishing portion of the injectorshell, to be brought into effective frictional contact with the inducedcolumn and saving the latter from retarding friction against the innerWall of the shell; also in having the delivery of the boosting column ofwater to the surrounding injector shell arranged through the medium ofan elbow or T-connection, the head of which constitutes a, chambercompletely surrounding the intake barrel at a distance which maintains awater supply materially larger in volume than that which passes theannular injector orifice, so that the boosting water, by 5 maintainingpressure in this large surrounding chamber, develops an injectingannulus of water that is uniform throughout its circumference and has avelocity of iiow that is materially greater than obtained in either ofthe previous l0 arrangements known to me, and especially the arrangementwhere the impelling water flows in a passage of approximately uniformsection composed of an outermost leg extending oppositely to the pumpingdirection and then abruptl5 1y reverses its flow through a constrictedbend which largely absorbs its energy as it enters an inner annular legleading toward the injector; or the previously known construction inwhich the boosting column meets the injector shell at 20 an obtuseangle, with the result that the boosting water is driven to the far sideof the shell where it deflects and develops spiral currents that aremuch less efficient in their induction effect upon the pumped uid; alsoin having a venturi im- 25 mediately following the jet orifice andhaving a part of the receiving end of this venturi formed by theconverging shell into which the orice discharges.

In order that the invention may be fully un- 30 derstood, the preferredembodiment thereof is shown, by Way of illustration, in the accompanyingdrawing, in which- Figure 1 is an elevational view of a portion of afloating vehicle upon which is mounted a con- 35 ventional dredging pumpof rotary type, and an auxiliary boosting water pump, together with thesuction pipe of the pump first named, the delivery pipe of the auxiliarypump, and the instrumentalities through which the remote ends 40 ofthese pipes are connected and associated after the manner of aninjector; and

Figure 2 is an axial section on an enlarged scale, of those portions ofFigure 1 having to do with the injecting or boosting feature of the 45invention.

A represents a portion of a vessel or floating vehicle mounting a rotarypump B of any appropriate conventional kind. C represents the axiallyassociated suction pipe of pump B, and D rep- 50 resents its tangentialdischarge pipe. Pipe C, through conventional intermediate connectionswhich may include a exible section E and any necessary length of rigidconduit F, leads from an intake barrel I through an interposed injector2, the impelling fluid of which preferably consists of Water suppliedthrough pipe G leading from auxiliary pump H having outboard submergedintakepipe I.

Intake barrel I is of such substantial length, say, for instance, five'or six times its diameter, as will cause it to develop. in response tosuction, a projectile or body of pumped fluid (dredged material with itsvehicular complement of water) filling its bore and largely free fromvortical disturbances, eddy currents or the like, so that upon reachingthe injector orice 3 in the choke shell 4 it will have substantialmomentum and 11npelling force stored in it. Shell 4 is forwardlytapering and in rear of orifice 3 unites with the cylindrical shell ofthe injector 2, which is in the form of a T-member, the head 5 of whichis of such materially greater diameter than the external diameter of thebarrel I which it surrounds, as to develop a substantial provisionalwater chamber 6 into which boosting water pipe G delivers through thestem 'I of the T in a direction perpendicular to the ow of the materialpumped, with the result that the provisional body of water in thechamber Ii, maintained by pump H, will cause an annulus of water to bedelivered at the orifice 3 which is substantially uniform in densityover its entire circumference, as well as at constant volume and speed.This annular water jet has a relatively high velocity in response topressure maintained in provisional reservoir 6, being free from flowobstructions other than jet opening 3A and enters the converging shell 4in full contact with the inner surface of the shell and with lubricatingeffect or elimination of frictional resistance upon the projectile ofwater flowing from barrel I, and thus produces altogether superiorimpelling'effect upon the fluid coming from the barrel. 8 represents aVenturi section in the pipe F that is conventional as to design andfunction, except that in the present instance its converging leg 8a ismaterially shorter than its diverging leg 8b, and the former is made upin part of the converging injector shell 4. Shell 4 andA convergingVenturi leg 8aare not necessarily of the same angle of convergence; infact, the angle of shell 4 is preferably greater thanV that of leg 8abut the two merge together with a minor change in angle and the shellthus serves as a portion of the venturi.

8.1:, 8am, and 4:1: represent bushings or liners for the elements 8, 8aand 4, which are readily replaceable when Worn away by erosion from thematerial pumped; the liners being preferably in abutment with theseveral flange couplings or held in column by an intervening ring 5, asmay be desired.

I0 represents a separately formed header for the head 5 of the T, andthis header is threaded upon the barrel I as shown and has associatedwith it a jamb nut II in order that barrel I may be adjusted axiallyrelatively to converging shell 4 in regulating the orifice 3.

A feature in the most approved design of the apparatus is the flare 3a.at the discharge end of the intake barrel I through which the inducedfluid projectile is enabled to meet the injecting annulus from theorifice 3 without eddy-forming offset that would result from an abruptbarrel section at thisv point.

The several elements of the injector, its associated parts, and thepipes which it connects are all made of readily assembled and easilyreplaceable parts, and the construction and assembly is such that a higheiciency of injector and propelling effect is obtained.

What is claimed is:

1. In dredging apparatus, an injector shell comprising a straight walltubular section terminating with flanged ends and having a laterallyoset intake opening intermediate said flanged ends, a choke shellco-axially joined to the injectorshell and having walls converging in adirection forward of the injector shell, a Venturi shell co-axiallyjoined to the restricted end of the choke shell and extending from andin advance thereof for a distance exceeding the length of the chokeshell, an intake barrel comprising a straight pipe section entering theinjector shell through one end thereof and extending coaxially throughthe same with its discharge end terminating within the choke shell inco-operating relation with the converging walls thereof, therebyproviding an annular orifice through which Water'is injected into thechoke shell from the injector shell, and means for axially adjusting theposition of the intake barrel relatively to the converging walls of thechoke shell for changing the effective port area of said orifice.

2 'Ihe combination as set forth in claim land in which the joint betweenthe injector shell and the choke holds a spider which embraces theintake barrel andserves; to support the forward end ofthe same. v

3. 'I'he combination as set forth in claim l and in which'thelength ofthe intake barrel is not less than three times its diameter.

HERMAN H. HOLLOWAY.

